1. Field of the Invention
The invention relates to magnetic tape drive systems, and more particularly, to a roller for use in a tape drive system.
2. Background Art
A tape drive is used to perform read and/or write operations on magnetic tape supplied by a tape cartridge. Such a tape drive may be provided with one or more rollers for guiding movement of the tape along a tape path, which extends between a supply reel of the tape cartridge and a take-up reel of the tape drive. Drive motors typically associated with the reels, and driven under control of a motor controller circuit, are used to control speed of the tape along the tape path. A tachometer associated with one of the rollers may be used to monitor speed of the tape by monitoring speed of the roller, and to provide input signals to the motor controller circuit indicative of tape speed.
If the tape slips on the roller, however, the tachometer will not provide an accurate indication of tape speed. Such slippage may be attributed, in part, to a thin film of air that flows between the tape and the roller and lifts the tape off the roller.
A prior solution for venting such an air film is disclosed in U.S. Pat. No. 5,088,172. The roller disclosed in that patent includes a helical groove that extends between opposite ends of the roller. Such a groove, however, may induce lateral movement in tape traveling across the roller, thereby causing data read and/or write errors. Moreover, lateral tape movement may cause the tape to impinge on a flange of the roller, thereby causing increased tape edge loading and tape edge wear.